Facial contortions of a bass player involving mouth twisting to the groove, chin dropping impossibly low, brow furrowing, a seemingly blank stare and a general unawareness of the condition. Also often accompanies Egyptian-style head gyrations.

1) a musical variation of the poker face in which the bass player of a given band wears an expression lacking any noticeable emotion, giving them an anonymous, emotionally distant appearance.

2) A bass face is the name given to the face a DJ or audiophile when a beat drops or a bassline is particularly compelling and gritty. This use of the term is used for electronic music, especially drum & bass, dubstep, and any other dance music where the main interest is the bassline.

1) "Did you see the show last night?"
"Yeah. The bass player took bass face to a new level. Fucker didn't even flinch the entire show."

2) ""Did you see DJ Sublo's face when that record hit?"

"Yeah, he must really enjoy that track, just look at his bass face! I can see why, this beat is filthy!"